1. Field of the Invention
The present invention relates to a plate-shaped optical data carrier comprising a layer transparent for radiation and an information recording layer on the surface of which memory areas for digital information are arranged, wherein said data carrier comprises a through opening for a receiving means of a reading and/or writing device.
2. Description of Related Art
Such data carriers are generally known by the names of CD (Compact Disc), CD ROM (Compact Disc Read Only Memory), and DVD (Digital Versatile Disc). Apart from solely readable types there are also types such as CD-R which allow the user to individually record information by using specific writing devices, possibly even as a rewriteable type (CD-RW).
The known data carriers are received at their central opening by an appropriate reading and/or writing device and rotated so as to realize a data flow from and to the data carrier by means of a radially movable reading and/or writing head emitting a laser beam.
The generally known prior art also includes so-called CD ROM cards having the thickness of a conventional CD ROM or DVD but mostly not having the standardized check card format. On such data carriers, the memory area is limited to a circular ring of the maximum possible diameter fitting into the roughly rectangular surface of the data carrier. Compared with conventional check cards comprising a magnetic strip or electronic chip elements, these CD ROM cards are remarkably thicker which is regarded as a disadvantage. This thickness significantly reduces their elasticity, which, if the CD ROM card is carried in a purse, adversely affects the carrying comfort of the latter. Also the free space in conventional wallets or purses often does not allow to receive a plurality of CD ROM cards. Also, the polycarbonate used to manufacture these CD ROM cards is disadvantageous for handling the card in typical rough everyday conditions as the brittleness of the material, in combination with its low elasticity, may easily cause the material to break or crack. DE 29616 619 U1 describes a so-called multimedia business card whose width and length are similar to the size of standard paper business cards. However, this known business card is made of CD ROM material with the thickness of the business card being equal to that of a normal CD ROM.
Such a so-called non-standard format of a CD or CD ROM cannot be used in all conventional players. DE 297 04 140 U1 thus discloses a CD player adapter, especially for the multimedia business card described in DE 296 16 619 U1. The outer dimensions of the body of the CD player adapter equal exactly the dimensions of a standard CD or CD ROM while said body comprises an inner through recess of a rectangular cross-section corresponding to the shape of the peripheral geometry of the multimedia business card. The business card can be fixed on the player adapter because its front sides have a convex shape while the front edges of the inner recess of the player adapter are of a matching concave shape. Due to the elasticity of the plastic material used to form the business card as well as the player adapter, the business card can be inserted into the recess using a certain force, thus ensuring a secure and defined connection of the two components due to the matching shapes in the inserted state. In order to facilitate the action of inserting or extracting the business card into or from the player adapter, widened rounded areas are provided in the corner areas of the inner recess.
Further, it is desirable to increase the variability of such data carriers with regard to various storage principles and the corresponding reading and writing methods.
It is an object of the present invention to provide a data carrier whose handling and keeping meet high comfort requirements and which is characterized by variability as regards the storage principles applied in data storage.
Based on a data carrier of the type described above, this object is achieved according to the present invention in that the thickness of the data carrier is smaller than the thickness of a standart data carrier of the DVD type but larger than the sum of the thickness of the information recording layer of a standard data carrier of the DVD type and of the minimum backing layer thickness required.
Due to its reduced thickness, such a data carrier offers good flexibility and therefore very comfortable handling. To carry even a plurality of such data carriers does not cause the space problems occurring with regard to conventional CD ROM cards. The thickness of the backing layer needs to be dimensioned only so small that the data carrier can be handled and transported without the risk of being damaged. As far as the data carrier comprises a layer transparent for radiation above the information recording layer, said transparent layer can completely take on the function of the backing layer ensuring the shape stability of the data carrier, so that the thickness of the layer transparent for radiation essentially defines the minimum thickness of the data carrier as the thickness of the information recording layer is extremely small. It is a fact that the reduction in thickness suggested according to the present invention causes the disadvantage that without further measures the data carrier cannot be read by the CD or DVD players which are presently in use. However, the present invention offers the tremendous advantage of providing an optical data carrier which due to all its dimensions, especially its thickness, is compatible with data carriers using other storage principles (magnetic strip card, chip card, . . . ) and thus can be used in a xe2x80x9cmultimediaxe2x80x9d manner.
Preferably, its thickness, length and width are equal to those of conventional chip cards or magnetic strip cards. According to the present standards, its thickness should be approximately 0.8 mm. Thus, the present invention provides for the first time an optical data carrier which, with respect to its dimensions and usability, is completely compatible with existing formats such as credit card, check card, chip card, and xe2x80x9csmart cardxe2x80x9d.
As a particularly advantageous feature of the present invention, the opening is arranged eccentrically and the data carrier is provided with an electronic chip element which is readable and/or writeable via contact surfaces.
In addition to its function as an optical data carrier, the data carrier according to the present invention further has the very advantageous feature of performing the function of a chip card. The space needed for the chip element, whose arrangement is standardized for known chip cards, is provided by eccentrically arranging the opening for the receiving means. When, for example, the center of the opening is arranged on the longer central axis of a rectangle defining the shape of the data carrier, the available storage area is not reduced as the size of the circular ring fitting onto the card remains unchanged compared with a central arrangement of said opening. The eccentric arrangement of the opening increases the safety of application as it is obvious to anybody not to use said card without an adapter. Otherwise, the card (even when having a central opening) cannot be used in slot drives and in the common drawer trays of PCs. However, this weak point also exists with respect to conventional CD cards.
Preferably, the layer transparent for radiation is made of polycarbonate.
In a further development of the present invention, it is provided to arrange the chip element on the side of the data carrier positioned opposite to the layer transparent for radiation.
In order to further enhance the functionality and compatibility of the data carrier with respect to different storage principles, it is suggested to provide the data carrier with a magnetic strip. It makes sense to arrange the magnetic strip as well as the chip element on the side of the data carrier positioned opposite to the layer transparent for radiation. In such case, it will really be a multimedia data carrier.
In order to meet higher aesthetic requirements of the data carrier and/or to provide the data carrier with specific security features, a further development of the present invention suggests to provide the side of the data carrier positioned opposite to the layer transparent for radiation with a coating, for example, in the form of a xe2x80x9cwatermarkxe2x80x9d or a hologram.
In a further development, the data carrier according to the present invention comprises a circular-ring memory member comprising the opening, a supporting member having the thickness, length, and width of a standard data carrier of the chip card type, and a chip element being readable and/or writeable via contact surfaces, wherein the memory member and the chip element are insertable into the support member in a manner providing essentially plane surfaces of the data carrier.
On the one hand, an annular memory member is easier to manufacture than a memory member of a different shape, and, on the other hand, different materials can be used for both members in order to meet the different requirements. Thus, the memory member is preferably made of polycarbonate having a high surface hardness while it makes sense to manufacture the supporting member of a flexible material less susceptible to breakage, cracking, or fatigue, for example, a plastic material or cardboard.
Furthermore, it is suggested that the memory member has a thickness between 0.5 mm and 0.6 mm and an outer diameter matching essentially the width of a standard data carrier of the chip card type in order to achieve the largest memory capacity possible of the data carrier.
In a preferred embodiment of the data carrier, the supporting member is at least in part made of hard cardboard. This offers the advantage that the user may individually print on the supporting member by laser printing, for example, for use as a business card. After printing, the memory member and, if applicable, the chip element may be inserted into the properly shaped respective recesses of the supporting member and be affixed, for instance, by gluing. Compared with conventional business cards, such business cards offer the advantage that, on the one hand, considerably more information can be stored while maintaining the flexibility of common chip cards, and, on the other hand, this information can be directly read into the data processing system of the recipient of the business card, thus making separate and time-consuming manual input of these data redundant.
Further, the present invention suggests an adapter to receive a data carrier, said adapter being provided with a receiving space whose inner dimensions are slightly larger than the outer dimensions of the data carrier to be received, and with a central opening arranged coaxially to the opening in the data carrier in its received position, wherein the sum of the thickness of the data carrier and the thickness of the adapter in the receiving space area is equal to the thickness of a standard data carrier of the DVD type and wherein the unit formed of the adapter and the data carrier is rotatable without balance error around the central axis of the opening.
This ensures in a simple manner the playability of the data carrier according to the present invention even at high revolution rates and independently from the model of the reading and/or writing device. Usually the user does not carry the adapter with him/her; the adapter is kept with the reading and/or writing device. One single adapter is sufficient for a plurality of similar data carriers. The adapter can, for example, be integrally formed by injection molding or assembled from two disks.